000 AXNT20 KNHC 060005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT Sat May 5 2018 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURE... An upper level cyclonic circulation center is along the Atlantic Ocean side of Cuba along 78W. Upper level cyclonic wind flow that is moving around the circulation center covers the area from SW corner of the Caribbean Sea to 28N in the Atlantic Ocean between 65W in the Atlantic Ocean and 90W in the Gulf of Mexico. A surface trough is along 80W from 20N northward, and from 20N80W to 16N80W and 10N77W. Precipitation: widely scattered moderate to isolated strong rainshowers cover the areas from 14N in the Caribbean Sea to 32N in the Atlantic Ocean between 68W and 80W. This feature was forecast by the computer models at the beginning of the week. The GFS model forecast, for 250 mb and 500 mb, shows that a cyclonic circulation center will stay on top of Cuba, weaken into a trough, and then move eastward. An upper level trough will move across the Gulf of Mexico toward Florida. The GFS model, from the surface to 700 mb, shows that a trough will move westward from its present position on top of Cuba and the Bahamas, to Florida, for the next few days. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea near 09N13W to 02N22W. The ITCZ continues from 02N22W, to 01N30W 01N43W, and to the Equator along 50W at the coast of Brazil. Precipitation: scattered moderate to strong rainshowers are from 03N northward between the Prime Meridian and 03W. widely scattered moderate to isolated strong rainshowers are from 05N southward between 10W and 32W. isolated moderate rainshowers are elsewhere from 08N southward. ...DISCUSSION... GULF OF MEXICO... A cold front is moving through the north central and NW corner of the Gulf of Mexico shortly. Broken to overcast multilayered clouds and possible rainshowers are to the NW of the line that runs from the Florida Panhandle into the SW corner of the Gulf of Mexico. The current cold front will move across the northern gulf waters through Sunday and exit the eastern gulf Sun night evening. High pressure building in the wake of the front will support gentle to moderate north to northeast winds over the area. These winds will change little through Tue night before becoming northeast to east in direction Wed through Thu, except for southeast to south winds over the far western gulf in return flow as the high pressure shifts to the northeast gulf. CARIBBEAN SEA... Please read the SPECIAL FEATURES section for more infomation about the upper level cyclonic circulation and surface trough near Cuba and the Bahamas. A tight surface pressure gradient between strong central Atlantic high pressure and a surface trough along 80W is providing for strong E to SE winds over the eastern half of the central Caribbean as well as over the western half of the eastern Caribbean. These winds will gradually diminish to fresh winds and become more E in direction Sun through Tue as the trough pulls off to the west- northwest while weakening and as the strong Atlantic high pressure weakens some. The combination of a large upper low over central Cuba, that is slowly moving south, and plenty of moisture and instability to its southeast will continue to bring scattered to numerous showers and thunderstorms over the eastern section of the central Caribbean through Mon. Scattered showers and isolated thunderstorms over much of the eastern are expected to continue through Tue. ATLANTIC OCEAN... Please read the SPECIAL FEATURES section for more infomation about the upper level cyclonic circulation and surface trough near Cuba and the Bahamas. The current north-to-south oriented surface trough will continue inland across the Florida peninsula this evening, and through Sun. Scattered to numerous showers and thunderstorms along with fresh to strong winds and seas to 10 ft are expected mainly to the east of the trough, while scattered showers and isolated thunderstorms will precede the trough. A weak cold front will enter the waters N of the Bahamas Sun evening and merge with the northern portion of the surface trough. The front will slow down as it reaches from near 31N78W to western Cuba Mon afternoon, then become stationary from near 31N75W to west-central Cuba late Mon night through Thu as it weakens. Weak low pres is expected to track northeastward along the front Mon through Tue. Fresh to strong southerly winds will precede the front over the waters north and northeast of the Bahamas through Mon night, then diminish to fresh winds late Mon night. The front will begin to slowly dissipate through Thu as high pressure ridging begins to build westward along 31N. For additional information please visit http://www.hurricanes.gov/marine $$ MT